I feel for the kid and his family. He didn't deserve to be shot, no. No one deserves to die for being stupid.
What's bugging me, though, is that he should have known better. I know, kids are stupid, but even I knew in my safe-as-hell neighborhood that you never throw things at people's house, or trespass, etc, after dark. This kid from Houston frankly should have known better - Texas castle laws are very, VERY slanted towards the homeowner in almost every respect. By the time I was 19, I for damn sure knew that if you threw or shot things at a house - paintballs, firecrackers, whatever - there was a significant chance you'd get shot. Cause everybody's got a gun.
It's much more difficult to sympathize with someone who did something he absolutely should have known better than to do than to sympathize with, say, the person who gets accidentally shot.